ARRHENIUS KINETICS FOR THE OXIDATION STABILITY, ANTIOXIDANT CAPACITY AND FATTY COMPOSITION OF LICURI (Syagrus coronata) AND BABASSU (Attalea speciosa) OILS FROM BRAZILIAN CAATINGA AND CERRADO

Brazilian Caatinga and Cerrado has a wide variety of plant species and provides the development of palm trees such as licuri and babassu, which can supply nutritional and financial resources for local communities. This work aimed to determine the Arrhenius kinetics for the oxidation stability, antioxidant capacity and fatty composition of oils from the seeds of licuri and babassu fruits. The activation energy of the Arrhenius kinetics was calculated using Rancimat data at temperatures of 383.15, 393.15, 403.15, and 413.15 K (AOCS Cd 12b-92); fatty acid profile and monoacylglycerol (MAG), diacylglycerol (DAG), and triacylglycerol (TAG) content were determined using gas chromatography (AOCS Ce 1-62 and Cd 11-b-91, respectively); free fatty acid (FFA) expressed as lauric acid was calculated through potentiometric titration (AOCS Cd 3d-63); the antioxidant capacity was determined by inhibitory concentration of 1,1-difenil-2-picrilhidrazil to 50% (DPPH IC50) using spectrophotometry, before and after heating to 473.15 K. Activation energies were 92.5±0.3 and 96.6±0.2 kJ.mol-1 for licuri and babassu oils, respectively. Licuri oil exhibited 88.63, 11.04 and 0.33% (by mass) of saturated, monounsaturated and polyunsaturated fatty acids, respectively; babassu oil presented 87.50%, 12.05% and 0.45% (by mass), respectively. Licuri oil presented 94.94% TAG, 4.03% DAG, 0.95% MAG, and 0.08% FFA (by mass), comparatively close to babassu oil with 96.01% TAG, 2.32% DAG, 0.73% MAG, and 0.94% FFA. DPPH IC50 of licuri oil was 173.4±0.2 mg.mL-1 before, and 375.5±0.2 mg.mL-1 after heating, while that of babassu oil was 155.2±0.6 mg.mL-1 before, and 210.1±0,1 mg.mL-1 after heating. These results demonstrate that the antioxidant compounds in licuri oil are more thermolabile than those presented in babassu oil. Both oils demonstrate high activation energy, which is directly related to their shelf life and oxidative stability. These characteristics add even more value to the natural resources from Brazilian Caatinga and Cerrado.